A bone is made of organic materials and inorganic materials. The organic materials include growth factors, soft bone tissues, collagen, other proteins, and the inorganic materials include calcium phosphate.
A bone grafting material needs to have a biocompatibility so as to facilitate natural regeneration in case of occurrence of defects or wounds of the bone. An ideal bone grafting material needs to have a bone generation function, that is, a bone conduction function and a bone induction function and to be easy to operate for surgery. In addition, strength and properties thereof needs to be maintained after the surgery.
A demineralized bone matrix (DBM) improves activity of bone generation protein included in the bone to increase the bone induction function and is easy to treat. Therefore, the DBM has been increasingly used for the bone grafting surgery, and the DBM is considered as an effective bone grafting material for treatment. In order to graft the DBM into a wound portion, a method of delaying absorption of the DBM, increasing the activity for combining with the bone, and being easily treated is required.
The DBM denotes a polymer material obtained by removing cells and inorganic materials from a bone. Since the DBM is a material for inducing hard tissue generation, various applications thereof are expected.
Since the DBM has an efficient bone regeneration capability, the DBM is used as a filler for a portion of a body where bone regeneration is slow or impossible in orthopedics, dentistry, neurosurgery, and the like. In addition, the DBM is used to replace a damaged portion of a bone and to fix and reinforce a joint. In addition, the DBM is used to treat an osteoma, a bone wound, and a bone fracture.
Since the DBM has a low compatibility to an aqueous solution due to a structure thereof, the DBM cannot easily maintain a desired shape when only the DBM is used for grafting. In addition, a bone generation protein included in the DBM may be digested in a body. Therefore, the DBM is not easy to maintain a shape and has a slow bone regeneration rate, so that the DBM becomes an incomplete replacement. In addition, since the DBM has no implantation ability, other materials are necessarily used for grafting of the DBM into a damaged portion of a bone.
According to current reports, since the DBM has low implantation ability due to the incomplete shape retentivity of the DBM, a composite of the DBM and polymers such as gelatin, glycerol, poloxamer, and hyaluronic acid has been used. However, the aforementioned stabilizers do not satisfy all the requirements of the shape retentivity, the implantation ability, the content, and the biocompatibility. For example, a composite including gelatin can improve the implantation ability of the DBM, but the composite is not easy to store and has a short expiration period
A method of grafting a mixture of the DBM and a synthetic polymer is also disclosed. However, since the mixture is not digested in a body, a compatibility to a body fluid is lowered, so that the mixture may damage kidney. In addition, a mixture of the DBM and glycerol is also disclosed. However, since the mixture has a very small content of the DBM, the bone regeneration function of the DBM may be lowered. In addition, a mixture of the DBM and hyaluronic acid is also disclosed. However, the grafting of a bone into is too rapidly digested in a body and production cost thereof is two high. In addition, due to the hyaluronic acid, a bone morphogenic protein (BMP) is easily exposed, so that the BMP is rapidly digested by an enzyme in a body. Therefore, the bone regeneration rate is lowered.
In order to solve the problems, there is a need for a composite capable of improving a biocompatibility, having no damage to a human body, improving an implantation ability and shape retentivity of a DBM, and having no fluidness after grafting.